Conventionally, an ink jet printer of a type in which an ink cartridge is mounted on a carriage is equipped with a maintenance mechanism which performs wiping operation for cleaning a printhead of the ink cartridge and capping operation for preventing the printhead from drying out.
As a prior art example of an ink jet printer maintenance mechanism of this kind, there exists an arrangement including a movable frame for performing wiping operation and a lever which locks in a forward moving position of the movable frame, the movable frame and the lever being provided as separate members, in which the lever attached to the movable frame via a spindle which serves as a connecting member locks the movable frame at its forward moving position and unlocks the movable frame by forward and reverse rotating motion of the lever (refer to Japanese Patent Application Publication No. 1993-096740, for example).
In the maintenance mechanism described in Japanese Patent Application Publication No. 1993-096740, however, it is necessary to separately mold the lever and the movable frame with synthetic resin since the lever and the movable frame which must be provided with the lever are configured as separate members. This causes not only a remarkable increase in manufacturing cost but also an increase in the number of components, which acts as an obstacle to achieving an overall cost reduction.
As a prior art example intended to overcome this obstacle, there exists an arrangement which makes it possible to reduce the number of components by one-piece molding a lever and a movable frame which must be provided with the lever with synthetic resin (refer to Japanese Patent Application Publication No. 2000-233517, for example).
A maintenance mechanism described in Japanese Patent Application Publication No. 2000-233517 is equipped with a 2-pen type ink cartridge and configured as shown in FIGS. 6(A) and (B), for example. FIG. 6 is a diagram showing an example of a conventional ink jet printer maintenance mechanism. As shown in the Figure, ink cartridges 51 are (detachably) mounted on a carriage 52 which is slidably supported by a metal frame 61 of an apparatus body. Guided by a guide shaft 62, the carriage 52 moves back and forth along a main scanning direction to allow the ink cartridges 51 to perform a print job.
Caps 53 for capping printheads of the ink cartridges 51 and wipers 54 for wiping the printheads are held by a slide member 56. Projections 56b of the slide member 56 are loosely fitted in guide holes 55b formed in a base member 55 which is fixed to the apparatus body such that the slide member 56 can slide obliquely leftward and rightward.
A claw member 57 for locking the slide member 56 during wiping operation is swingably supported on the slide member 56 via a pivot 57a. The claw member 57 is always biased clockwise as illustrated by a tension spring 59, whereby the slide member 56 is biased leftward down as illustrated.
FIG. 6(A) shows a condition in which the heads of the ink cartridges 51 are capped by the caps 53. In this condition, the slide member 56 is connected to a right side portion of the carriage 52 via a slide member/carrier joint part 56a and pushed up to an uppermost position.
FIG. 6(B) shows a condition in which the ink jet printer has transferred to a state of performing a print job. In this condition, the slide member 56 is brought back obliquely leftward down by a tensile force exerted by the tension spring 59 and stops at a lowermost position after passing the wiper positions. At the same time, the claw member 57 moves leftward and goes into a state in which the claw member 57 does not mutually interfere with a protruding part 52a which is attached to a lower-right portion of the carriage 52, where the carriage 52 is allowed to move to a print position as illustrated.
When attention is given to a mutual relationship of the positions of the wipers 54 and the claw member 57 in a left/right direction (main scanning direction), it is seen that an upper-left projecting part of the claw member 57 is located at a position further to the left of the left-hand wiper 54, that is, at a position close to a sheet transport area, in the maintenance mechanism of Japanese Patent Application Publication No. 2000-233517 shown in FIG. 6. Therefore, to avoid interference between the claw member 57 and the protruding part 52a of the carriage 52 and between the claw member 57 and a sheet, it is necessary to place the claw member 57 farther away from the sheet transport area by a distance necessary for avoiding the interference. This causes an increase in the width of the apparatus as much as that distance.
If the upper-left projecting part of the claw member 57 is located at the same position as the wiper 54 along the left/right direction as illustrated, for example, the slide member 56 is once locked by the claw member 57 at about a mid-length position of each guide hole 55b in the base member 55 during wiping operation. However, since the protruding part 52a of the carriage 52 meshes with the projecting part of the claw member 57 and the slide member 56 is unlocked subsequently before the wipers 54 wipe entire nozzle faces of the ink cartridges 51, the wipers 54 descend obliquely leftward down together with the slide member 56, causing a risk of inadequate wiping of the nozzle faces as a consequence.
In the aforementioned structure of the conventional ink jet printer maintenance mechanism in which the claw member 57 is pivotably supported on the slide member 56, the claw member 57 is located closer to the sheet transport area than the wipers 54 during a printing process, so that it is necessary to enlarge the interval between the sheet transport area and the wipers 54. It is therefore difficult to reduce the width of the apparatus as mentioned above.
Also, an ink jet printer of a type in which an ink cartridge is mounted on a carriage has not conventionally been provided with any damper placed between a main chassis and a slide member for maintenance in a moving direction of the carriage. For this reason, an inertial force of the slide member for maintenance would be transmitted directly to the main chassis or a main body when the slide member for maintenance returns back to its original position, causing severe vibration and colliding sound.
The present invention has been made in light of such circumstances. Accordingly, it is an object of the invention to provide an ink jet printer maintenance mechanism which makes it possible to reduce apparatus width and alleviate vibration of the maintenance mechanism and colliding sound caused thereby at reversing motion of a carriage.